I am doing past tax returns for a client 2019-2020.

Client had rental property since 2012 but doing her own taxes did not take any depreciation.

i would like to take it in 2019, but she sold the property in 2020 and would benefit more by filing the 3115 in 2020 instead of 2019 (the first year of discovery technically). My preference would be to offset cap gains on the sale of the house.

Can she claim depreciation in 2019 and then file the 3115 for 2020 to take missed depreciation.

Or does she have to file the 3115 for 2019 for the first year of discovery?